Burglar alarm



BURGLAR ALARM Filed July 21, 1951 rzverzfir 022965; 621

Patented Nov. 3, 1931 puirsu issatsa OTWELL c. Pn'r'rYJeHn, or PHILADELrHL PENNSYLVANIA.

'IBURGLAR AL RM Application filed July 21 19 31. Serial No, 552,175.

My invention relates to newand useful improvements in a burglar alarm and especially to that type of such alarms as which serve to lock the upper and lcwer sash of a window against being opened from the outside and has for its object to provide a bell so mounted that it may be swung over the upper rail of the lower sash of a window or out of alignment therewith for putting into and out of operative positions.

A further object of my invention is to provide for an automatic spring action which will always tend to put the alarm in operative position upon the closing of the lower 1 sash.

A still further object of my invention is to so construct the device that it will be cheap to manufacture, simple to apply and easy to operate.

Q lVith these and other ends in View, this invention consists in the details of construction and combination of elements hereinafter set forth and then specifically designated by the claims.

In order that those skilled in the art to which this invention appertains may understand how to make and use the same I will 2 describe its construction in detail, referring by numerals to the accompanying drawings forming a part of this application, in

5 which Fig. 1 is an elevation of a portion of a window frame and the sashes fitted thereto showing my improved burglar alarm applied to 5 the frame and in operative position relative to the sashes.

Fig. 2 is a view at right angles to Fig. 1.

Fig. 3 is a section at the line 33 of Fig. 2, looking downward and showing the alarm *9 set in operative position in full lines and just prior to being set in such position, in

dotted lines.

In carrying out my invention as herein embodied, 10 represents the alarm bell which is of the type commonly known as a bicycle bell, the ringing mechanism thereof being enclosed within its two halves and the trip rod 11 thereof projecting through a hole in one of the halves and carrying a head or bottom 9 12. This bell I mount upon a swinging 13' by mean's of th e bridge 14;, said arm prefi i erably' tapering outward and extending beyond the bellas clearly shown in'Fig; 2. i F

1 5 representsa, plate similar to one leaf of a hinge and this plate is adapted tobe' secured to the inner faceof ajwindow frame by the screws 16 passing through suitable holes in said plate. g M

The'arm 13 is pivoted'to the plate 15 by the pintle 17 passing through the lugs18 on the" plate'and the lug 19 on the arm so as to perfmitthe arm to freely swing relative to the plate while'giving iteonsiderable strength to resist strains in a vertical direction for the purpose heretoforeset forth.

20 represents'a spring coiled around a'por- W tion of the pintle 17 the lower'lug"18beingv left shorter than the upper lug 18 to provide space forthe accommodation of this-spring. One end ofthis spring bears against the outer surface of thearm 13 as indicatedat 21, while the opposite end thereof projects downward against the lower lug 18 as indicated at 22 and this arrangement will cause the spring to constantly exert the pressureupon the'ar'm tending to swingsaid arm inward. From the foregoing description, the operation of my improvement will he obviously as follows, the plate l5'having been secured tofthe inner f'face of the window frame as shown and the lower sash havingbeen closed, the arm will be swung by the spring-into operative position bringing the button 12 of the trip rod'immediately above the upper rail ofthe lower sash-a'fter which any attempt to raise the lower sash will force the trip rod E 11 upward tripping the ringing mechanism of the bell, thereby continuing to sound-an alarm until the ringing mechanism ofthe bell has been run down or the lower sash has been closed, thusproviding effective protec tion against an unauthorized person gaining access -throughthe window. x i When the bell is in operative position, it not only provides for the setting off of the alarm on an attempt tobemade toraise' the lower sash, but it also looks the lower sash against being raised to any ap'preciable e);- tent, since the-bell and the arm carrying the Same being inthe path oftravel of this sash will prevent the raising of the latter, the arm and plate being of sufiicient strength to resist any ordinary attempt to raise this sash.

When the bell is swung into operative position, the outer end'of the arm 13 projects beneath the screw stud 23 set in the side rail of the upper sash, thus locking this upper sash against being opened.

a bridge secured upon the arm, and a trip bell mounted upon the bridge, the outer end of said arm extending beyond the bell.

In testimony whereof, I have hereunto affixed my signature.

OTWELL Gr. PETTYJOHN.

To free the two sashes so that they may be e opened is only necessary to swing the arm outward against the action of the spring until said arm and the bell carried therebyhave passed out of the paths of said sashes and by slightly raising the lower sash the outer end of the arm'will abut against thelower sash as indicated at 23 thereby holding the alarm out of active position so long as the sash is open, but upon the closing of the sash, the

-, spring will immediately swing the arm into operative position thus eliminating the possibility of being left unprotected by a person forgetting to set the alarm. This is one: of.

the essential features of my presentinyention since the usual burglar alarm requires manual setting or adjustment to put itin position for operation and by oversight it is often left unset and the window left unprotected,

but when my device is used no care or thought on the part of the person closing the window a plate 'havinsgjhole's therethrough for the passage of screws to secure said plate to a 7 window frame. an arm pivoted to the plate a,

by a pintlepassing through lugs formed upon the plate anda lug formed upon the arm. a

spring coiled upon a portion of the pintle between one of the lugs of theplate and the lug of the arm, one end ofsaid spring'bear-' ing against the outer surface ofthe arm. the other end of said spring bearing against a lug of the plate, a trip bell secured to the arm in such a manner that when the arm is closed against the plate the trip of the bell willbe positioned above the upper rail of thelower sash of the window and means secured to the upper sash in the path of the outer. end. of the arm when the latter is-closed against the g V plateJf' 2. In a device of the character described, a plate having two lugs formedv thereon, an arm having a' lug formed on one end thereof,

, a pintle passing through the lugs to hinge the arm to the plate, a spring coiled arounda portion of the pintle,- said spring being adapted to swing the arm toward the plate, 

